From my own personal experiance here in the UK I have found that some (not all) "big box stores" rebrand power tools. It was not unusual for the replacement parts from a brand name tool fit a shop brand and vice-verca.
This is not uncommon in the electrical appliance trade or even the auto trade.
Big company Merlonie own and produce machines under the names Indesit, hotpoint and creda to name just some.
Just like Volkswagon own the brands Audi,Seat and others. So the model numers are relevant.
Also I do not know how the "Consumer act" works in the US but here the law states that "all products must last a reasonble lenth of time"
" in England this is accepted to be 6 years and in Scotland 5 years"
"the retailer is reponsible for this warrenty and your 1 year manufatures garentee is in addititon to you rights"
Hal - perhaps if you have something simmlier in the states this is why you were told to contact the retailer